Mineral oil composition



Patented Feb. 20, 1951 MINERAL OIL COMPOSITION Louis A. Mikeska and Paul V. Smith, Jr., Westfield, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 2, 1948, Serial No. 63,188

This invention pertains to extreme pressure lubricants and compositions for imparting extreme pressure or load carrying properties to lubricating oils. The invention also pertains to a method for preparing extreme pressure agents, incorporating elements such as sulfur, phosphorus, and the like, in such a manner that they will be available for suitable chemical activity under heavy load conditions.

As is well understood in the art, ordinary mineral base lubricating oils and greases which are used to lubricate opposed metal surfaces are likely to fail under extremely heavy load conditions. For example, certain machine elements such as the hypoid gears commonly used in automotive vehicles, may be subjected at times to extremely heavy pressures of the order of hundreds of thousands of pounds per square inch. 'If the film of lubricating oil separating the opposed elements fails, as it is likely to do under such pressure, the surfaces will contact each other directly, generating high temperatures due to friction, with resultant seizure or excessive wear and early failure. Extreme pressure additives containing active sulfur, phosphorus, or chlorine, or two or more of these, are effective to react immediately with the metal surfaces at their higher temperatures to form a protective metal sulfide, phosphide, or chloride film which serves temporarily as a lubricating medium until the normal oil film between the parts can be reestablished. Extreme pressure additives are, therefore, reactive with the metals they lubricate to form extremely thin protective films thereon when the temperature rises due to normal oil film failure.

It is known to the art (J. Inst. Petr., v. 31; 73 (1945) that the presence of a ClsCgroup in a compound tends to impart extreme pressure properties thereto. For example, condensation products of chloral with mercaptans such as ethyl, n-butyl, isobutyl, phenol, benzyl, thioglycollic acid, thiosalicyllic acid and mixed petroleum mer captans in the boiling range 20 to 50 C. are good extreme pressure additives.

It has now been found that compositions having extreme pressure properties and other desirable properties for use in lubricating oil compositions and the like may be prepared by treating chloral or its hydrate with a mercaptan to form the hemimercaptal of chloral which itself is an excellent oiliness and extreme pressure agent. The fur-p 6 Claims. (Cl. 252-46.6)

ther reaction of chloral hemi-mercaptals with phosphorus pentasulfide or phosphorus sesquisulfide gives products which impart exceptional oiliness and extreme pressure properties to min eral oil blends. Equally efiective products can be obtained by converting the hemi-mercaptals to alkali xanthates which are in turn condensed with sulfur dior monochloride to yield the corre spond polysulfides.

The hemi-mercaptals are prepared simply by treating chloral or its hydrate with the desired mercaptan. Mercaptans containing from 2 to 20 carbon atoms may be used. However, mercaptans having from 8 to 20 carbon atoms are preferred.

Simple hemi-mercaptals of chloral are reacted with phosphorous pentasulfied by refluxing the reactants in the presence of some solvent such as dioxane, toluene, etc. By reacting simple hemimercaptals first with carbon disulfide and an alkali, a xanthate may be formed which, by reaction with sulfur dichloride, forms the desired xanthogen trisulfied. S2012, S0012, or ClSCCh may be used in place of sulfur dichloride.

Generally, the products of this invention may be represented by the generalized formula,

wherein R represents an alkyl group, X represents H in the case of simple hemi-mercaptals and in the case of xanthogen trisulfied, Y represents sulfur or oxygen, and n represents the integer Per cent Phosphorus 0.044 Sulfur 17.88

Chlorine 25.86

In producing the additives of the present invention, chloral hydrate is simply heated together with a suitable mercaptan. A solvent such as dioxane may be used if desired. The reaction time may vary from 0.25 to 3 hours. The hemi-mercaptal thus formed may be used as such or it may be further reacted with P235 by simply refluxing the entire mixture for 3 hours. The xanthogen trisulfide is formed by reacting the chloral hemi-mercaptal with sodium or potassium hydroxide and an excess of carbon disulfide. then reacted with sulfur dichloride by refluxing in the presence of a solvent such as benzene.

It will be understood that compositions of the types referred to in the present application may be added in various quantities to various typeset oils as will be obvious to. thoseskilled in. the: art. They may be added to relatively lightoils, such as oils of automotive engine grades, for the purpose of increasing oxidation stability, al.- though normally they will be used more widely in heavier oils, such as SAE 80, 90, or 1&0 grade for the lubrication of hypoid gears orother machine elements encountering extreme, pressure conditions. They may a-so be used in cutting, oils, in soluble cutting oi s in conjunction with sodium sulfonates and with other appropriate emulsifying agents. For use in gear oils, proportions of 5% to 20% by weight of the additives 1 are preferred, being a common useful proportion. It will be understood, however, that proportions as low as about 1% may be employed. For concentrates, to be added to oils by the consumer according to his needs, the additive products of this invention maybe marketed straight or in 10% to 80% solutions. in. mineral oil of appropriate grade. The mineral lubricating oils having viscosities between about 35 S. S. U. and

1,000 S. S. U. at 210 F. are. preferred.

Various conventional additives may be employed in connection with the extreme pressure compounds described above, such as thickeners, oiliness agents, oxidation inhibitors, tackiness agents, viscosity index improvers, pour point .depressants, and the like. These materials. may also be used in greases thickened with, soaps, carbon blacks, silica gels and other known grease-forming materials.

The invention will be more fully understood byreference to the following examples:

Example I Gradual. Shock 'lortiary-octyl hemi-mercaptal of chloral l5 l5 Tertiary-dodeeyl hemianercaptal of chloral 13 Tertiary-hexadecyl hemi-rnercaptal of chloral 15 11 Example II Samples oftertiary-octyl, tertiary-dodecyl and The metal xanthate thus formed is,

tertiary-hexadecyl hemi-mercaptals of chloral, prepared in accordance to the procedure of Example I, were treated with phosphorus pentasulfide. The reaction products were tested in the Almen machine with the following results:

Gradual Shock Product from Tertiary-octyl hemi-mercaptal of chloral Product from Tertialy-dodecyl hemi-mercaptal Example III I Gradual Shock Product from Tertiary-octyl hemi mercaptal of ol'chloraln l5 l3l4 Product from Te tiary-hexadecyl hemi-mercaptal oi chloral l5 9-40 What is claimed is:

l. A- composition consisting: essentially of" a mineral oil base stock containing 1% to 20% by weight based on total composition, of acompound having the formula wherein R represents an alkyl. group containing from 2 to 20. carbonatoms, and Y represents, an element selected from. the classconsisting of oxygen and sulfur;

2.- A. composition consisting essentially; of a mineral oil base stock containing from 1% to 20% by Weight based on a total composition, Of a compound having theformula wherein- R representsan'alkyl? group containing 2 to 20 carbon atoms.

3; A composition consisting. essentially of a mineral oil base stock containing from 1 %:to 20 by weight, based on total composition, of a com? pound having the formula r Ono-o-on r wherein R. represents an alkyl group containing from 2 to 20 carbon atoms.

4. A composition consisting essentially of a mineral oil base stockcontaining from 1% to 20% by weight, basedon total composition, of a compound having the formula 5 6 '5. A composition consisting essentially of a REFERENCES CITED mineral oil base stock containing from 1% to 20% The followino references are of record in the by weight, based on total composition, of a comfile of this patient pound having the formula H 5 UNITED STATES PATENTS 12 25 ClaC- OH Number Name Date 2,228,252 Berger et a1 Jan. 14, 1941 2,247,045 Berger et a1. June 24, 1941 6. A composition consisting essentially of a 2,329 .324 Berger et a1 Sept. 14, 1943 mineral oil base stock containing 1% to 20% by 10 weight based on the total composition, of a com- OTHER REFERENCES pound having the formula Pages 527-530 of the Journal of the Institute of Petroleum, vol. 33, 1947. Article by Davey entitled Some Extreme Pressure Lubricating Oil 15 Additives.

LOUIS A. MIKESKA. PAUL V. SMITH, JR. 

1. A COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL OIL BASE STOCK CONTAINING 1% TO 20% BY WEIGHT BASED ON TOTAL COMPOSITION, OF A COMPOUND HAVING THE FORMULA 